【米CDC】布およびサージカルマスクを重ねることでフィット感改善し、SARS-CoV-2の感染伝搬・曝露低減がなされる #ダブルマスク #二重マスク (2021.2.11作成)

日付切取線 @krtr_date

✄----------- 2/11(木祝) ----------✄

That's Interesting @innneresting

The CDC has today updated its guidance on masks: 1. Cloth mask over a surgical mask (Fig B) OR... 2. 'Tying off' surgical masks (Fig C) Both approaches reduced exposure by ~95% (i.e comparable to N95 masks at 95%) CDC stressed the importance of fit. cdc.gov/mmwr/volumes/7… pic.twitter.com/khD88mTGlm

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Eric Feigl-Ding @DrEricDing

BREAKING—CDC urges either **double-masking** or use **surgical mask with tight fit** to better protect against threat of new and more contagious variants of the coronavirus. Two methods substantially boost fit & protection, says CDC report. #COVID19 🧵 washingtonpost.com/health/2021/02… pic.twitter.com/yA8HvpZnXt

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Eric Feigl-Ding @DrEricDing

2) “We know that universal masking works,” said John T. Brooks, medical officer for CDC’s covid-19 response. “And now these variants are circulating … whatever we can do to improve the fit of a mask to make it work better, the faster we can end this pandemic.”

Eric Feigl-Ding @DrEricDing

3) “One is wearing a cloth mask over a surgical mask. The second is improving the fit of a single surgical mask by knotting the ear loops and tucking in the sides close to the face to prevent air from leaking out around the edges and to form a closer fit.” pic.twitter.com/N6Ru5S4qNf

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Eric Feigl-Ding @DrEricDing

4) Both of those methods reduced exposure to potentially infectious aerosols by more than 95 percent in a laboratory experiment using dummies, the report said.

Eric Feigl-Ding @DrEricDing

5) A three-ply surgical mask blocked 42 percent of particles from a simulated cough, and a three-ply cloth mask blocked 44 percent. But a cloth mask covering a medical mask blocked 92 percent of the particles, the report said.

Eric Feigl-Ding @DrEricDing

6) In a second experiment, a dummy wearing double masks and one wearing a knotted/tucked medical reduced exposure for an unmasked dummy by 82 percent and 62 percent respectively....

Eric Feigl-Ding @DrEricDing

7) When one dummy was not wearing any masks and the one acting as the bystander wore a double mask or a knotted/tucked medical mask, the bystander’s exposure was reduced by 83 and 64.5 percent respectively...

Eric Feigl-Ding @DrEricDing

8) ...But when both dummies wore double masks or knotted/tucked medical masks, the bystander’s exposure was reduced by more than 95 percent in both situations!!

Eric Feigl-Ding @DrEricDing

9) @linseymarr offered these tips for ensuring the best mask fit: “You should not be able to see or feel any kind of open spots around the edges of your mask, especially around your nose, which is why a metal bridge is so important for fitting tightly around the nose.

Eric Feigl-Ding @DrEricDing

10) “You don’t want gaps around the cheek or chin. One way you can check when you are breathing, does it feel like air is leaking out of the side? Put your hand on the edge to see if you feel anything. When you breathe in, you should feel suction up against your face.”

Eric Feigl-Ding @DrEricDing

11) Other signs of leakage include eyeglasses fogging up or cold breath coming from the sides of masks while outside. Another test involves breathing hard in front of a mirror to see if you blink while wearing a mask, which would indicate leakage from the top of the mask.

Eric Feigl-Ding @DrEricDing

12) “If masks fail these tests, Marr said, you should try a different kind of mask. “Peoples’ faces have such different shapes that you can try to find something that can work better for your face,” she advised.

Eric Feigl-Ding @DrEricDing

13) Key is to avoid the critical side gap in the mask! cdc.gov/mmwr/volumes/7… pic.twitter.com/wjMpU5iMM6

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Eric Feigl-Ding @DrEricDing

14) INTERESTING DETAIL—While both people wearing masks is best (green circle), if only one person out of 2 wears a mask, the double mask (of surgical plus cloth) seems superior to single surgical that is knotted & tucked. All else equal—do both. But if just do one, DOUBLE MASK. pic.twitter.com/vsP7caFBLl

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Eric Feigl-Ding @DrEricDing

15) VIDEO—I think the knotted & tucked surgical mask is tricky for people to understand without a full video. Here is the video to demonstrate how to do it. youtube.com/watch?v=2TTg53… (HT @Arriadna) pic.twitter.com/45yjNPA06O

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Eric Feigl-Ding @DrEricDing

16) Here is @CDCDirector @RWalensky explaining the new double masking / tight surgical mask guidance today. pic.twitter.com/lbeBow73aT

Eric Feigl-Ding @DrEricDing

17) Getting lots of N95 / KN95 mask questions — assuming you have one, and it’s a real one (not a knock off, @projectn95 can advise), the key thing is again FIT. I’ve seen many KN95 that have bad fit. Nose bridge should be tight. Use straps if available. Ear loops stretch tight.

Eric Feigl-Ding @DrEricDing

18) ⚠️ONE-PARTY MASKING UNEQUAL: ➡️If only one person is masked, is it better if the source (exhaling person) is masked, or if the air receiver (inhaler) is masked for someone inhaling risk? 💡CDC study: **Source-masking** (red) is much better for minimizing exposure! pic.twitter.com/oxcxNnsRbe

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Eric Feigl-Ding @DrEricDing

19) I’m shocked that the CDC report didn’t emphasize this! This is a serious problem in areas with many unmasked!! ⚠️In fact, it almost looks like there is little to no difference if the source of the exhaled air is not masked vs neither masked (yellow circle!). Damn—Not good. pic.twitter.com/xtGWK4WZqn

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Eric Feigl-Ding @DrEricDing

20) Luckily, it looks like if you follow the new CDC guidance on either double masking or the enhanced surgical mask fit, then it matters less if the source of the 3rd party air is not masked. You are still protected!! pic.twitter.com/olQyDYVDYA

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Eric Feigl-Ding @DrEricDing

21) Here is the best demonstration video of how to tie the new surgical mask properly. twitter.com/drericding/sta…

Eric Feigl-Ding @DrEricDing

PROPER WAY TO KNOT & FOLD SURGICAL MASKS, per new CDC guidelines (see 🧵 below for details why). Special thanks to Dr Rabeeh Bahrampourian. #COVID19 #maskup youtube.com/watch?v=2TTg53… pic.twitter.com/lozFQ2JBMs twitter.com/DrEricDing/sta…

2021-02-11 03:02:38

Eric Feigl-Ding @DrEricDing

22) Another surgical mask folding demonstration, from wonderful folks at @GMA. pic.twitter.com/0tgqcHIbyo